1. Field of the Invention
The present invention relates generally to wave engines and more particularly relates to wave engines used to drive electric generators. Specifically, the present invention relates to wave driven generators using a plurality of different sized floats to present a black body to the incoming wave energy whereby wave energy is nonlinearly coupled into hydraulic pumping means.
2. Background of the Prior Art
It has long been known in the art of power generation to use the potential energy available in ocean waves to lift a float. A truely amazing variety of ingenious mechanical linkages have been developed in an attempt to efficiently capture the energy of ocean waves. See, for example, U.S. Pat. Nos. 562,317, 632,139, 694,242, 738,996, 886,883, 917,411, and 986,629. All of these early patents rely upon mechanical linkages between fixed floats to trap the rocking, lifting, falling or longitudinal motions of waves. All of the engines disclosed in these patents are mechanically complex and highly inefficient.
While all the above cited references depend on the potential energy of waves to develop motive power, some wave motors in the past taught the use of the wave's kinetic energy. See, for example, U.S. Pat. No. 1,072,272.
A careful study of the prior art show that most historical wave motors utilize either (1) the kinetic energy of waves by devices such as paddle wheels, or (2) the wave's potential energy by a float or a series of floats. Few devices utilize both forms of energy.
The prior art, insofar as it relates to wave engines that rely upon the lifting power of waves, i.e., its potential energy, rely either on a single float, for example U.S. Pat. Nos. 1,202,742, 1,471,222, 1,647,025, 1,746,613, 1,953,285 and 1,962,047, or utilize a series of floats of the same size, for example U.S. Pat. Nos. 1,925,742, 1,867,780, 1,688,032, 1,567,470, and 1,408,094. Additionally, many early wave motors are extremely complex mechanically. For example, see U.S. Pat. Nos. 1,528,165, 1,169,356, and 1,818,066.
All prior art wave motors teach the direct linear coupling of the float's motion through either mechanical or hydraulic means to the motion of a shaft or piston. As a result, all such wave motors had to be very rugged and heavy to withstand the wide spectrum of wave energy incident upon them. For example, one wave motor installed in Atlantic City, New Jersey consisted of six foot cylinder floats 4 feet high. Each float weighed about 3,100 pounds and was lifted two feet by waves 11 times per minute. They drove a horizontal shaft by means of chains and rachets, developing about 11 horsepower, steadiness being obtained by the use of heavy flywheels. The inefficiency, capital cost and complexity of this and all prior art wave motors caused them to be unsuccessful. (Power, Jan. 17, 1911). (A similar wave motor was proposed by Smith in Mechanical Engineering, September, 1927 at page 995).
The most modern wave motors taught by the prior art does not differ significantly in its manner of operation from wave engines taught at the beginning of this century. See, for example, U.S. Pat. No. 3,879,950, issued Apr. 29, 1975 to Kiichi Yamada for a wave generator to be used in conjunction with an offshore nuclear power plant. This modern wave motor uses a plurality of identical floats whose motion is coupled linearly to a series of pneumatic pistons. Unfortunately, such a linearly coupled collector cannot efficiently trap wave energy.
Waves in the ocean vary in amplitude, or wave height, from a fraction of a foot to over 50 feet and in frequency from a wave length of less than 5 feet to over 1,000 feet. To extract the maximum potential energy from any given wave, a float must be capable of dynamically coupling to the wave's movement. A given size float will respond most efficiently to only one wave length. To be efficient, a wave motor must provide a plurality of different size floats capable of coupling efficiently into a broad spectrum of differing wavelengths, i.e., to all the waves from which power must be efficiently extracted. Broadly, this concept is called "resonance".
In addition to resonance with a broad spectrum of wavelengths, the floats of an efficient wave motor must be capable of extracting power from both low and high amplitude waves. Because waves differ in amplitude by as much as two orders of magnitude, any device that extracts power by linearly coupling wave movement to gears or pistons will have to be inefficient in extracting power from either the high or low amplitude end of the wave power spectrum.
Theoretically, an single float acting alone, even if it is the proper size, can only absorb about one third of the available power from a wave incident upon it. This is caused by the fact that a third of the wave's energy is absorbed by the float, a third is reflected back from the float and the final third is transmitted through the float to its attached structures. This fact, as well as the fact that wave motors taught by the prior art do not couple efficiently into either the frequency or amplitude spectrum of ocean waves, have caused all prior art wave motors to be very inefficient.
It is an object of the present invention to teach a wave engine that is capable of extracting hydraulic power efficiently from a wide variety of wavelengths of ocean waves.
It is a further object of the present invention to provide a wave engine that couples into the amplitude spectrum of ocean waves in a nonlinear manner so as to efficiently extract power from both high amplitude and low amplitude waves.
It is yet a further purpose of the present invention to provide a wave generator whose multiple floats act together to form a black body trapping all incident wave energy.
It is yet another purpose of the present invention to provide a wave engine having an assemblage of different size floats that function together as a wave trap to convert approximately 80% of the wave energy incident upon it to hydraulic power.
Yet a final purpose of the present invention is to provide a wave motor that can easily be scaled up to provide a large amount of power cheaply and that is simple enough to require a low level of maintenance.
After an extended search at the Patent Office, the closest art found to the present invention is U.S. Pat. No. 1,757,166 covering an apparatus and method of obtaining power from ocean waves. However, even this prior art teaches the use of a plurality of single unconnected floats of the same size. No prior art found by the inventor teaches the advantages of tying together a group of floats in an array to form a wave trap to capture reflected and transmitted wave energy. Also, no prior art found by the inventor teaches the nonlinear coupling of the floats to their associated power extraction devices.